245/40-17 vs. 235/40-17 Differences
Diameter inches (mm)24.72 (627.8)24.4 (619.8)-0.31 (-8) -1.3%
Width inches (mm)9.65 (245)9.25 (235)-0.39 (-10) -4.1%
Circum. inches (mm)77.65 (1972.29)76.66 (1947.16)-0.99 (-25.13) -1.3%
Sidewall Height inches (mm)3.86 (98)3.7 (94)-0.16 (-4) -4.1%
Revolutions per mile (km)815.98 (507.02)826.51 (513.57)10.53 (6.54) 1.3%
They roll at slightly different speeds, so your limited slip might be wearing out faster than normal. Me, I would get a matched size pair just for that. I think the main concern is if they are the same make/model tire. The same tire in two sizes really close to each other like you have should ride and handle the same. If a different brand, or even different model of the same brand with different tread, I would think they would ride and handle differently. In that case, I would definitely get a matched pair. That's just me, though....